/**
 * @author mrdoob / http://mrdoob.com/
 */
const THREE = require('../../three.js');

THREE.OBJLoader = (function () {

	// o object_name | g group_name
	var object_pattern = /^[og]\s*(.+)?/;
	// mtllib file_reference
	var material_library_pattern = /^mtllib /;
	// usemtl material_name
	var material_use_pattern = /^usemtl /;
	// usemap map_name
	var map_use_pattern = /^usemap /;

	var vA = new THREE.Vector3();
	var vB = new THREE.Vector3();
	var vC = new THREE.Vector3();

	var ab = new THREE.Vector3();
	var cb = new THREE.Vector3();

	function ParserState() {

		var state = {
			objects: [],
			object: {},

			vertices: [],
			normals: [],
			colors: [],
			uvs: [],

			materials: {},
			materialLibraries: [],

			startObject: function (name, fromDeclaration) {

				// If the current object (initial from reset) is not from a g/o declaration in the parsed
				// file. We need to use it for the first parsed g/o to keep things in sync.
				if (this.object && this.object.fromDeclaration === false) {

					this.object.name = name;
					this.object.fromDeclaration = (fromDeclaration !== false);
					return;

				}

				var previousMaterial = (this.object && typeof this.object.currentMaterial === 'function' ? this.object.currentMaterial() : undefined);

				if (this.object && typeof this.object._finalize === 'function') {

					this.object._finalize(true);

				}

				this.object = {
					name: name || '',
					fromDeclaration: (fromDeclaration !== false),

					geometry: {
						vertices: [],
						normals: [],
						colors: [],
						uvs: [],
						hasNormalIndices: false,
						hasUVIndices: false
					},
					materials: [],
					smooth: true,

					startMaterial: function (name, libraries) {

						var previous = this._finalize(false);

						// New usemtl declaration overwrites an inherited material, except if faces were declared
						// after the material, then it must be preserved for proper MultiMaterial continuation.
						if (previous && (previous.inherited || previous.groupCount <= 0)) {

							this.materials.splice(previous.index, 1);

						}

						var material = {
							index: this.materials.length,
							name: name || '',
							mtllib: (Array.isArray(libraries) && libraries.length > 0 ? libraries[libraries.length - 1] : ''),
							smooth: (previous !== undefined ? previous.smooth : this.smooth),
							groupStart: (previous !== undefined ? previous.groupEnd : 0),
							groupEnd: - 1,
							groupCount: - 1,
							inherited: false,

							clone: function (index) {

								var cloned = {
									index: (typeof index === 'number' ? index : this.index),
									name: this.name,
									mtllib: this.mtllib,
									smooth: this.smooth,
									groupStart: 0,
									groupEnd: - 1,
									groupCount: - 1,
									inherited: false
								};
								cloned.clone = this.clone.bind(cloned);
								return cloned;

							}
						};

						this.materials.push(material);

						return material;

					},

					currentMaterial: function () {

						if (this.materials.length > 0) {

							return this.materials[this.materials.length - 1];

						}

						return undefined;

					},

					_finalize: function (end) {

						var lastMultiMaterial = this.currentMaterial();
						if (lastMultiMaterial && lastMultiMaterial.groupEnd === - 1) {

							lastMultiMaterial.groupEnd = this.geometry.vertices.length / 3;
							lastMultiMaterial.groupCount = lastMultiMaterial.groupEnd - lastMultiMaterial.groupStart;
							lastMultiMaterial.inherited = false;

						}

						// Ignore objects tail materials if no face declarations followed them before a new o/g started.
						if (end && this.materials.length > 1) {

							for (var mi = this.materials.length - 1; mi >= 0; mi--) {

								if (this.materials[mi].groupCount <= 0) {

									this.materials.splice(mi, 1);

								}

							}

						}

						// Guarantee at least one empty material, this makes the creation later more straight forward.
						if (end && this.materials.length === 0) {

							this.materials.push({
								name: '',
								smooth: this.smooth
							});

						}

						return lastMultiMaterial;

					}
				};

				// Inherit previous objects material.
				// Spec tells us that a declared material must be set to all objects until a new material is declared.
				// If a usemtl declaration is encountered while this new object is being parsed, it will
				// overwrite the inherited material. Exception being that there was already face declarations
				// to the inherited material, then it will be preserved for proper MultiMaterial continuation.

				if (previousMaterial && previousMaterial.name && typeof previousMaterial.clone === 'function') {

					var declared = previousMaterial.clone(0);
					declared.inherited = true;
					this.object.materials.push(declared);

				}

				this.objects.push(this.object);

			},

			finalize: function () {

				if (this.object && typeof this.object._finalize === 'function') {

					this.object._finalize(true);

				}

			},

			parseVertexIndex: function (value, len) {

				var index = parseInt(value, 10);
				return (index >= 0 ? index - 1 : index + len / 3) * 3;

			},

			parseNormalIndex: function (value, len) {

				var index = parseInt(value, 10);
				return (index >= 0 ? index - 1 : index + len / 3) * 3;

			},

			parseUVIndex: function (value, len) {

				var index = parseInt(value, 10);
				return (index >= 0 ? index - 1 : index + len / 2) * 2;

			},

			addVertex: function (a, b, c) {

				var src = this.vertices;
				var dst = this.object.geometry.vertices;

				dst.push(src[a + 0], src[a + 1], src[a + 2]);
				dst.push(src[b + 0], src[b + 1], src[b + 2]);
				dst.push(src[c + 0], src[c + 1], src[c + 2]);

			},

			addVertexPoint: function (a) {

				var src = this.vertices;
				var dst = this.object.geometry.vertices;

				dst.push(src[a + 0], src[a + 1], src[a + 2]);

			},

			addVertexLine: function (a) {

				var src = this.vertices;
				var dst = this.object.geometry.vertices;

				dst.push(src[a + 0], src[a + 1], src[a + 2]);

			},

			addNormal: function (a, b, c) {

				var src = this.normals;
				var dst = this.object.geometry.normals;

				dst.push(src[a + 0], src[a + 1], src[a + 2]);
				dst.push(src[b + 0], src[b + 1], src[b + 2]);
				dst.push(src[c + 0], src[c + 1], src[c + 2]);

			},

			addFaceNormal: function (a, b, c) {

				var src = this.vertices;
				var dst = this.object.geometry.normals;

				vA.fromArray(src, a);
				vB.fromArray(src, b);
				vC.fromArray(src, c);

				cb.subVectors(vC, vB);
				ab.subVectors(vA, vB);
				cb.cross(ab);

				cb.normalize();

				dst.push(cb.x, cb.y, cb.z);
				dst.push(cb.x, cb.y, cb.z);
				dst.push(cb.x, cb.y, cb.z);

			},

			addColor: function (a, b, c) {

				var src = this.colors;
				var dst = this.object.geometry.colors;

				if (src[a] !== undefined) dst.push(src[a + 0], src[a + 1], src[a + 2]);
				if (src[b] !== undefined) dst.push(src[b + 0], src[b + 1], src[b + 2]);
				if (src[c] !== undefined) dst.push(src[c + 0], src[c + 1], src[c + 2]);

			},

			addUV: function (a, b, c) {

				var src = this.uvs;
				var dst = this.object.geometry.uvs;

				dst.push(src[a + 0], src[a + 1]);
				dst.push(src[b + 0], src[b + 1]);
				dst.push(src[c + 0], src[c + 1]);

			},

			addDefaultUV: function () {

				var dst = this.object.geometry.uvs;

				dst.push(0, 0);
				dst.push(0, 0);
				dst.push(0, 0);

			},

			addUVLine: function (a) {

				var src = this.uvs;
				var dst = this.object.geometry.uvs;

				dst.push(src[a + 0], src[a + 1]);

			},

			addFace: function (a, b, c, ua, ub, uc, na, nb, nc) {

				var vLen = this.vertices.length;

				var ia = this.parseVertexIndex(a, vLen);
				var ib = this.parseVertexIndex(b, vLen);
				var ic = this.parseVertexIndex(c, vLen);

				this.addVertex(ia, ib, ic);
				this.addColor(ia, ib, ic);

				// normals

				if (na !== undefined && na !== '') {

					var nLen = this.normals.length;

					ia = this.parseNormalIndex(na, nLen);
					ib = this.parseNormalIndex(nb, nLen);
					ic = this.parseNormalIndex(nc, nLen);

					this.addNormal(ia, ib, ic);

					this.object.geometry.hasNormalIndices = true;

				} else {

					this.addFaceNormal(ia, ib, ic);

				}

				// uvs

				if (ua !== undefined && ua !== '') {

					var uvLen = this.uvs.length;

					ia = this.parseUVIndex(ua, uvLen);
					ib = this.parseUVIndex(ub, uvLen);
					ic = this.parseUVIndex(uc, uvLen);

					this.addUV(ia, ib, ic);

					this.object.geometry.hasUVIndices = true;

				} else {

					// add placeholder values (for inconsistent face definitions)

					this.addDefaultUV();

				}

			},

			addPointGeometry: function (vertices) {

				this.object.geometry.type = 'Points';

				var vLen = this.vertices.length;

				for (var vi = 0, l = vertices.length; vi < l; vi++) {

					this.addVertexPoint(this.parseVertexIndex(vertices[vi], vLen));

				}

			},

			addLineGeometry: function (vertices, uvs) {

				this.object.geometry.type = 'Line';

				var vLen = this.vertices.length;
				var uvLen = this.uvs.length;

				for (var vi = 0, l = vertices.length; vi < l; vi++) {

					this.addVertexLine(this.parseVertexIndex(vertices[vi], vLen));

				}

				for (var uvi = 0, l = uvs.length; uvi < l; uvi++) {

					this.addUVLine(this.parseUVIndex(uvs[uvi], uvLen));

				}

			}

		};

		state.startObject('', false);

		return state;

	}

	//

	function OBJLoader(manager) {

		THREE.Loader.call(this, manager);

		this.materials = null;

	}

	OBJLoader.prototype = Object.assign(Object.create(THREE.Loader.prototype), {

		constructor: OBJLoader,

		load: function (url, onLoad, onProgress, onError) {

			var scope = this;

			var loader = new THREE.FileLoader(scope.manager);
			loader.setPath(this.path);
			loader.load(url, function (text) {

				try {

					onLoad(scope.parse(text));

				} catch (e) {

					if (onError) {

						onError(e);

					} else {

						console.error(e);

					}

					scope.manager.itemError(url);

				}

			}, onProgress, onError);

		},

		setMaterials: function (materials) {

			this.materials = materials;

			return this;

		},

		parse: function (text) {

			var state = new ParserState();

			if (text.indexOf('\r\n') !== - 1) {

				// This is faster than String.split with regex that splits on both
				text = text.replace(/\r\n/g, '\n');

			}

			if (text.indexOf('\\\n') !== - 1) {

				// join lines separated by a line continuation character (\)
				text = text.replace(/\\\n/g, '');

			}

			var lines = text.split('\n');
			var line = '', lineFirstChar = '';
			var lineLength = 0;
			var result = [];

			// Faster to just trim left side of the line. Use if available.
			var trimLeft = (typeof ''.trimLeft === 'function');

			for (var i = 0, l = lines.length; i < l; i++) {

				line = lines[i];

				line = trimLeft ? line.trimLeft() : line.trim();

				lineLength = line.length;

				if (lineLength === 0) continue;

				lineFirstChar = line.charAt(0);

				// @todo invoke passed in handler if any
				if (lineFirstChar === '#') continue;

				if (lineFirstChar === 'v') {

					var data = line.split(/\s+/);

					switch (data[0]) {

						case 'v':
							state.vertices.push(
								parseFloat(data[1]),
								parseFloat(data[2]),
								parseFloat(data[3])
							);
							if (data.length >= 7) {

								state.colors.push(
									parseFloat(data[4]),
									parseFloat(data[5]),
									parseFloat(data[6])

								);

							} else {

								// if no colors are defined, add placeholders so color and vertex indices match

								state.colors.push(undefined, undefined, undefined);

							}

							break;
						case 'vn':
							state.normals.push(
								parseFloat(data[1]),
								parseFloat(data[2]),
								parseFloat(data[3])
							);
							break;
						case 'vt':
							state.uvs.push(
								parseFloat(data[1]),
								parseFloat(data[2])
							);
							break;

					}

				} else if (lineFirstChar === 'f') {

					var lineData = line.substr(1).trim();
					var vertexData = lineData.split(/\s+/);
					var faceVertices = [];

					// Parse the face vertex data into an easy to work with format

					for (var j = 0, jl = vertexData.length; j < jl; j++) {

						var vertex = vertexData[j];

						if (vertex.length > 0) {

							var vertexParts = vertex.split('/');
							faceVertices.push(vertexParts);

						}

					}

					// Draw an edge between the first vertex and all subsequent vertices to form an n-gon

					var v1 = faceVertices[0];

					for (var j = 1, jl = faceVertices.length - 1; j < jl; j++) {

						var v2 = faceVertices[j];
						var v3 = faceVertices[j + 1];

						state.addFace(
							v1[0], v2[0], v3[0],
							v1[1], v2[1], v3[1],
							v1[2], v2[2], v3[2]
						);

					}

				} else if (lineFirstChar === 'l') {

					var lineParts = line.substring(1).trim().split(" ");
					var lineVertices = [], lineUVs = [];

					if (line.indexOf("/") === - 1) {

						lineVertices = lineParts;

					} else {

						for (var li = 0, llen = lineParts.length; li < llen; li++) {

							var parts = lineParts[li].split("/");

							if (parts[0] !== "") lineVertices.push(parts[0]);
							if (parts[1] !== "") lineUVs.push(parts[1]);

						}

					}

					state.addLineGeometry(lineVertices, lineUVs);

				} else if (lineFirstChar === 'p') {

					var lineData = line.substr(1).trim();
					var pointData = lineData.split(" ");

					state.addPointGeometry(pointData);

				} else if ((result = object_pattern.exec(line)) !== null) {

					// o object_name
					// or
					// g group_name

					// WORKAROUND: https://bugs.chromium.org/p/v8/issues/detail?id=2869
					// var name = result[ 0 ].substr( 1 ).trim();
					var name = (" " + result[0].substr(1).trim()).substr(1);

					state.startObject(name);

				} else if (material_use_pattern.test(line)) {

					// material

					state.object.startMaterial(line.substring(7).trim(), state.materialLibraries);

				} else if (material_library_pattern.test(line)) {

					// mtl file

					state.materialLibraries.push(line.substring(7).trim());

				} else if (map_use_pattern.test(line)) {

					// the line is parsed but ignored since the loader assumes textures are defined MTL files
					// (according to https://www.okino.com/conv/imp_wave.htm, 'usemap' is the old-style Wavefront texture reference method)

					console.warn('THREE.OBJLoader: Rendering identifier "usemap" not supported. Textures must be defined in MTL files.');

				} else if (lineFirstChar === 's') {

					result = line.split(' ');

					// smooth shading

					// @todo Handle files that have varying smooth values for a set of faces inside one geometry,
					// but does not define a usemtl for each face set.
					// This should be detected and a dummy material created (later MultiMaterial and geometry groups).
					// This requires some care to not create extra material on each smooth value for "normal" obj files.
					// where explicit usemtl defines geometry groups.
					// Example asset: examples/models/obj/cerberus/Cerberus.obj

					/*
					 * http://paulbourke.net/dataformats/obj/
					 * or
					 * http://www.cs.utah.edu/~boulos/cs3505/obj_spec.pdf
					 *
					 * From chapter "Grouping" Syntax explanation "s group_number":
					 * "group_number is the smoothing group number. To turn off smoothing groups, use a value of 0 or off.
					 * Polygonal elements use group numbers to put elements in different smoothing groups. For free-form
					 * surfaces, smoothing groups are either turned on or off; there is no difference between values greater
					 * than 0."
					 */
					if (result.length > 1) {

						var value = result[1].trim().toLowerCase();
						state.object.smooth = (value !== '0' && value !== 'off');

					} else {

						// ZBrush can produce "s" lines #11707
						state.object.smooth = true;

					}

					var material = state.object.currentMaterial();
					if (material) material.smooth = state.object.smooth;

				} else {

					// Handle null terminated files without exception
					if (line === '\0') continue;

					console.warn('THREE.OBJLoader: Unexpected line: "' + line + '"');

				}

			}

			state.finalize();

			var container = new THREE.Group();
			container.materialLibraries = [].concat(state.materialLibraries);

			for (var i = 0, l = state.objects.length; i < l; i++) {

				var object = state.objects[i];
				var geometry = object.geometry;
				var materials = object.materials;
				var isLine = (geometry.type === 'Line');
				var isPoints = (geometry.type === 'Points');
				var hasVertexColors = false;

				// Skip o/g line declarations that did not follow with any faces
				if (geometry.vertices.length === 0) continue;

				var buffergeometry = new THREE.BufferGeometry();

				buffergeometry.setAttribute('position', new THREE.Float32BufferAttribute(geometry.vertices, 3));

				if (geometry.hasNormalIndices === true) {

					buffergeometry.setAttribute('normal', new THREE.Float32BufferAttribute(geometry.normals, 3));

				}

				if (geometry.colors.length > 0) {

					hasVertexColors = true;
					buffergeometry.setAttribute('color', new THREE.Float32BufferAttribute(geometry.colors, 3));

				}

				if (geometry.hasUVIndices === true) {

					buffergeometry.setAttribute('uv', new THREE.Float32BufferAttribute(geometry.uvs, 2));

				}

				// Create materials

				var createdMaterials = [];

				for (var mi = 0, miLen = materials.length; mi < miLen; mi++) {

					var sourceMaterial = materials[mi];
					var materialHash = sourceMaterial.name + '_' + sourceMaterial.smooth + '_' + hasVertexColors;
					var material = state.materials[materialHash];

					if (this.materials !== null) {

						material = this.materials.create(sourceMaterial.name);

						// mtl etc. loaders probably can't create line materials correctly, copy properties to a line material.
						if (isLine && material && !(material instanceof THREE.LineBasicMaterial)) {

							var materialLine = new THREE.LineBasicMaterial();
							THREE.Material.prototype.copy.call(materialLine, material);
							materialLine.color.copy(material.color);
							material = materialLine;

						} else if (isPoints && material && !(material instanceof THREE.PointsMaterial)) {

							var materialPoints = new THREE.PointsMaterial({ size: 10, sizeAttenuation: false });
							THREE.Material.prototype.copy.call(materialPoints, material);
							materialPoints.color.copy(material.color);
							materialPoints.map = material.map;
							material = materialPoints;

						}

					}

					if (material === undefined) {

						if (isLine) {

							material = new THREE.LineBasicMaterial();

						} else if (isPoints) {

							material = new THREE.PointsMaterial({ size: 1, sizeAttenuation: false });

						} else {

							material = new THREE.MeshPhongMaterial();

						}

						material.name = sourceMaterial.name;
						material.flatShading = sourceMaterial.smooth ? false : true;
						material.vertexColors = hasVertexColors;

						state.materials[materialHash] = material;

					}

					createdMaterials.push(material);

				}

				// Create mesh

				var mesh;

				if (createdMaterials.length > 1) {

					for (var mi = 0, miLen = materials.length; mi < miLen; mi++) {

						var sourceMaterial = materials[mi];
						buffergeometry.addGroup(sourceMaterial.groupStart, sourceMaterial.groupCount, mi);

					}

					if (isLine) {

						mesh = new THREE.LineSegments(buffergeometry, createdMaterials);

					} else if (isPoints) {

						mesh = new THREE.Points(buffergeometry, createdMaterials);

					} else {

						mesh = new THREE.Mesh(buffergeometry, createdMaterials);

					}

				} else {

					if (isLine) {

						mesh = new THREE.LineSegments(buffergeometry, createdMaterials[0]);

					} else if (isPoints) {

						mesh = new THREE.Points(buffergeometry, createdMaterials[0]);

					} else {

						mesh = new THREE.Mesh(buffergeometry, createdMaterials[0]);

					}

				}

				mesh.name = object.name;

				container.add(mesh);

			}

			return container;

		}

	});

	return OBJLoader;

})();

module.exports = exports = THREE.OBJLoader;